The present invention relates to apparatus for and a method of manufacturing spindles and in particular to a method of rigidly fixing secondary components such as flanges to a spindle.
Spindles in the form of cylindrical elongated rods are widely used in mechanical devices. Spindles may be used to transmit both axial and rotational forces between components of a machine and it is known to provide secondary components such as keys, keyways, splines and flanges on the spindle to facilitate such force transmission. Spindles may also comprise threaded portions and/or undercuts to facilitate attachment of the spindle to other components and reaction points such as the chassis in a vehicle. An example of the use of a spindle is as a mounting for a spring means in a vehicle seat adjuster. The spindle is provided with a flange at a point along its longitudinal axis against which one end of the spring means abuts. Axial force is transmitted from the spring means to the spindle (and then onto either a further component or a reaction point) through the flange. As can be readily appreciated the joint between the flange and the spindle undergoes shear stresses commensurate with the axial force imparted to the spring means.
It is known to attach secondary components such as keys and flanges to the central spindle by means of welding or soldering. However, soldering can result in a joint between the secondary component and the spindle which is too weak to transmit the required forces. Welding, whilst providing a strong joint requires aggressive heating of the components which can be deleterious to the strength and hardness properties of the spindle and/or flange. Soldering and welding can also result in an unacceptably uneven surface to the secondary component and spindle in the vicinity of the joint and are processes which are labour intensive, slow and expensive to carry out.
The present invention provides in a first aspect a method of manufacture of a product from a first component of deformable material and a second component, the method comprising the steps of:
inserting a portion of the first component through an aperture predefined in the second component; and subsequently
deforming the material of the first component to form a pair of spaced apart shoulders integral with the first component, the spaced apart shoulders holding therebetween the second component and thereby preventing the second component sliding along the first component; wherein:
each shoulder is formed by applying tool means to a surface of the first component to create a recess in the surface and to form the shoulder adjacent to the recess with the shoulder being formed by displacement of the deformable material of the first component during the creation of the recess.
The present invention provides in a second aspect apparatus for fixedly locating of a first component having a cylindrical portion a second component having an aperture therein of a diameter chosen such that the second component is mountable on, and freely slidable along the cylindrical portion of the first component, the apparatus comprising: freely rotating means for supporting the first component;
first and second shafts disposed parallel to one another, at least one of the first and second shafts being movable in a plane perpendicular to its axis in a direction towards the other shaft;
means for rotating the first and second shafts;
first and second roller means axially spaced apart positioned on each shaft, the first and second roller means each having first and second inclined surfaces of differing inclinations and the first and second inclined surfaces of the first roller means on one shaft having inclinations which match the inclinations of the first and second inclined surfaces of the first roller means on the other shaft and the first and second inclined surfaces of the second roller means on one shaft having inclinations which match the inclinations of the first and second inclined surfaces of the second roller means on the other shaft; wherein:
the first and second shafts are moved towards each other to engage the first and second roller means of each shaft with the first component, with the engagement of the roller means with the first component generating forces which act to force the first and second roller means towards each other, such force arising due to the differing inclinations between the first and second inclined surfaces of each roller means; and the engagement of the roller means with the first component can deform material of the first component on either side of the second component with the forces applied to the first component forming thereon raised shoulders, the raised shoulders being located on both sides of the second component and fixedly locating second component on the first component.
The present invention provides apparatus for use in an automatic method for fixing secondary components, such as flanges, to spindles without soldering or welding which results in a joint strong enough to transmit high axial and rotational forces between the spindle and secondary component and yet does not require external or aggressive heating of the spindle and/or secondary component.
The present invention provides a quicker, safer, stronger and more precise method of jointing secondary components to spindles than is known in the state of the art.